The present invention relates to a material based on a non-woven textile lap which may be used as reinforcement for impermeable coverings constituted by a support embedded in a bitumen composition.
Such impermeable coverings based on bitumen reinforced by a textile structure have been known for a very long time.
The most ancient is the one used by Noah to construct his ark.
In fact, as the Old Testament clearly states, in Genesis Chapter 6, Verse 14, before the flood, God said to Noah: "Make yourself an ark with ribs of cypress; cover it with reeds and coat it inside and out with pitch" (New English Bible version).
This clearly shows that water-tight materials based on bitumen reinforced by a structure serving as support were known.
Since that time, such materials have always been used, particularly for making roofing for buildings. The reinforcements were, of course, developed at the same time as new textile materials and/or structures based on these materials appeared in the market.
For instance, it has been proposed to use chemical films, woven fabrics, non-woven fabrics, based on synthetic or inorganic matters (glass for example) as reinforcements.
It has also been envisaged to use felts based on glass fibers, woven or non-woven structures (French Pat. Nos. 1 330 291, 1 491 454), and even to make non-woven/woven fabric complexes in which the different layers are joined together by seams (U.S. Pat. No. 3,044,146) and/or to associate laps based on different textile material. For example, a non-woven fabric made of polyester and a web of glass fibers.
However, not all the materials up to the present time enable a fibrous complex to be obtained economically at a high speed, easy to manipulate, and to store and which presents all the qualities required when desired to make an one-layer impermeable covering, namely very good mechanical properties, a dimensional stability and an excellent punch resistance, both from the static and dynamic standpoint.
The most appropriate material answering all these characteristics is, according to the present invention, constituted by a complex formed by a non-woven fabric made of polyester associated on one of its faces with a textile grid made of glass.
The complex is marketed by Applicants under reference 603 GP 70.
The complex gives very good results but requires complex installations for making it.
A novel type of fibrous complex has now been found, and is the subject matter of the present invention which not only makes it possible to obtain the characteristics desired for the impermeable covering based on bitumen and more particularly one-layer coverings, but also may be produced at high speed, easy to store and to handle, presents a very good dimensional stability and an excellent punch resistance both from the dynamic and static standpoint.